I just finished doing a two day lapping event with BMW Club Quebec at mont tremblant race track and I havent had an issue with limp mode. I was really worried that my chipped 135i was going to have this problem but it didnt.
To prevent overheating, I flushed my coolant with 70/30 mix and a bottle of water wetter. I also installed a BMS oil cooler thermostat bypass, and changed my oil the day before the event. It was really hot and humid during the two track days, and I didnt have to install a aftermarket oil cooler
Just thought id share...